FIELD OF THE INVENTION
The invention relates to a method and an apparatus for ascertaining an air value to be made the basis for mixture preparation, upon pulsations of air in an intake tube of an internal combustion engine, and to a system for mixing an air/fuel mixture in an internal combustion engine on the basis of the air value ascertained with the method.
In order to provide correct mixture preparation, fuel metering systems require accurate information regarding the mass of air aspirated by the engine per stroke. They receive such information through fast-response air flow rate meters, which operate according to the hot-film principle, for instance. Due to the high response speed, the output signal of the air flow rate meter follows every pulsation in the air flow. Even air masses that are flowing backward are detected, although with the wrong sign. As soon as such pulsations occur, the air flow rate meter therefore no longer furnishes any correct measurement values that could be usable for mixture preparation.